DaWorstPlaya

iTrader: (31)

ButtDyno is correct about the R1-Rs. Having run STS pretty seriously, I have experience with the Toyos. The special Toyos sizes 195 and 235 had the sticky compound all the way through the tread. All other sizes had the softer sticky stuff on the outside and harder stuff underneath, perhaps to meet the 140 treadwear rating for that size. If they worn down to 4/32nds or got shaved to 4/32nds they just didn't have the same grip.

I ran both full tread and shaved 195 Toyos and the difference was night and day. The compound felt like pencil erasers to the touch because it was so soft. Full tread R1-Rs would over heat and grain pretty easily. Thus you didn't get any feed back (audio or otherwise) from the tires when they let go. They were also on average 1 sec slower from my comparative testing. Once they got down to 4/32nds (if they hadn't heat cycled out) they were like magic and the feedback was direct. You actually started to hear them when they were getting close to the limits of traction.

The R1-R were too soft for heavier car (such as the EVO) and would probably chuck or wear out too fast. There is a new 200 TW rated Toyo coming out but I don't see how the compound is going to be the same to meet the 200TW rating.



It could be a tire worth looking into.

Also, we have the Hankook RS3 V2 that is supposed to work better at a lower temperature range, so supposedly its fast from the 1st run. And it seems to work on the surface at nationals.

There is the Bridgestone RE11A that no one in the National scene seems to be using. GRM tests say its a pretty decent tire with the best wet traction all of them.

The Dunlop Direzza 2 Starspecs are out but there aren't any official Tirerack comparative reviews out for this tire. While looking around I found the following through one of the FR-S forums:

http://www.autocross.us/forums/topic...zii-star-spec/

It seems the guys at TireRack have done some testing but haven't done it officially.

While at Nationals this year I heard, BFG was supposedly testing a new Rival compound. Since the current Rivals don't do that well on the concrete suface at Nationals. But who knows if that is going to meet the April 2015 deadline.

So it seems its between the Hankooks and the Dunlops for now, since we have no data on the newer tires.

One of the guys on our local forum that has built National Championship winning cars in the past, mentioned going wider with street tires on a stock size rim is ultimately faster, according to his testing, but turn in and feel got worse. But others have contradicted that (eg: Andy Hollis). I don't have the wheel and tire budget to test sizes and tire brands simultaneously but I do use telemetry regularly. So perhaps when I make the switch mid year I can try to do a comparo if the 1st set isn't heat cycled out.

Mr.AWD are you running full tread tires or are you shaving them? How long do a set last for you?

MrAWD

I think than we were all saying the same thing about the 195s and their special status...

I kept the full thread on mine and after a whole season (which is just about 50 runs or so), there is barely any wear on them. Here is a picture of one of mine:

I will be flipping them to the other side for the next season and from what I can see right now, they will heat cycle out way earlier than they run out of rubber.

Now, considering all of that would I shave my next set? I am not sure at this time, but it did cross my mind.

Prime12

Is there a consensus on the relationship between track width and autocross performance?

So SCCA rules permit 1/4" offset changes either way. Is there any benefit on running spacers or wheels with less offset to maximize track width? Common sense says yes (wider track = more grip) but I think I've read Terry Fair saying narrower track width is actually advantageous in slaloms .

MrAWD

I think we have read the same thread from Terry and interestingly enough, that section caught my eye as well! When I bought my wheels, I also got a set of spacers to bring the wheels out a bit, but never decide to try it. I was under impression that soft OEM springs would suffer even more due to decreased wheel rates. If I was able to place bigger springs in there, that would be better way to go for sure. But, with requirement to keep stock springs in there, that could be only helped somewhat with better dampers.

Another reason why I didn't try the spacers is stock wheels studs, which will be replaced with ARP set before the next season. Than, I will test it out to see my self what will happen.

I am also quite interested what others have to say about this.

Fedja

EVO8LTW

iTrader: (41)

I can see how increasing the track width would be detrimental in slaloms if the tires are the widest part of the car, but if they are tucked into the fenders, then maybe the issue has more to do with dulled steering response caused by the greater scrub radius.

DaWorstPlaya

iTrader: (31)

You guys bring up some good points. They way I see it, going wider decreases lateral load transfer on which ever end becomes wider, which usually equals more grip. So it could be used as a very minor tuning tool. Just because the wheel rates gets slightly lower doesn't mean you'll lose grip but you may get more body roll.

Going wider on all sides also means the car will become more turn happy/unstable, where as going narrower makes the car more stable. Going narrower will theoretically make the car faster in slaloms but you'll lose on sweepers and vice versa. So the advantage will be course dependent. But I think on an average auto-x course being faster in the slaloms is generally quicker.

IMHO, on a production cars like ours, the difference should be very minor to negligible.

Right now I'm more concerned with which tire to get next.

WRC-LVR

iTrader: (1)

Probably more from the type/brand of tyre than the width. the rubber compostion/carcass side walls may have more effect than the width

DaWorstPlaya

iTrader: (31)

So, after looking at the fitment of 235 wide tires on a 8" wide rim. I've decided 255 is the widest I'm willing to go on an 8" wide rim. Got myself 2 sets of black Enkei RPF1s. 1 will be for rain tires, the other for shaved competition street tires. Now I just need to figure what tire to go with. It's going to be a toss up between the Hankook R-S3 and the Dunlop Z2 Starspec.

MrAWD

If you are planning on winning some of the Tours and/or Pros (Nationals of course), contingency is worth looking at as well. It would be nice if Dunlop would up their game, but I have heard nothing on this so far.

Another thing is that Bridgeston and Kumho are going to be with 200 tires, so I would check for those too.

Finally, BFG was planning some improvement after testing they did on Nationals course last year, so they could have a good thing as well.

Unless Toyo improves heat tolerance, I don't believe it will be an option for us.

After all of that, RS3 V2 still seem to be the one to have before any new testing is done.

Fedja

DaWorstPlaya

iTrader: (31)

Looking at the tread block design of the newer R1R, I don't think it will be a good tire for heavier cars. Those blocks look too tiny. Bridgestone has their RE-11A which is a decent tire and apparently has pretty good wet performance. Is there any info on the Kumho offering?

I'm leaning towards the Hankook R-S3 V2 due to cheaper price and the possibility of contingency. Although I'm very unlikely to get close to pocketing any wins. I'll have a better idea once the local summer season starts. We have a winter auto-x coming up this weekend and I'm contemplating running my EVO8 .... hrm

MrAWD

Might be helpful for this years decision making related to which tire to get:
http://www.tirerack.com/tires/tests/...y.jsp?ttid=197
Although, some are missing and Yoko is 180, while BFG is old model, take it at the face value...

Fedja

DaWorstPlaya

iTrader: (31)

Good find.

Here's Bridgestone's new tire that's coming out as well. RE-71R. Supposedly 1.4% faster.

http://www.bridgestone.co.jp/corpora...014120802.html

kyoo

iTrader: (29)

sad i didn't find this convo earlier - i've thought the same, but ultimately it's too far to go to back to stock class for me. i think if anyone's (somehow) got a stock ix rs, it's probably the only evo that has anywhere near a chance.

rear sway bar, not front sway bar, is probably going to be the best shot. stock rear diff restack will help with powering out of corners.

on the mini i'm racing in HS, i went with custom valved bilstein sports, and a couple of other tricks to get the car loose. keep in my mind lincoln concrete is disgustingly grippy, a car neutral anywhere else will probably understeer there.

MrAWD

I know for sure that X is soft enough that choosing rear bar is not the way to go for stock car. If IX is on the same page (and I think it actually is), FSB would help you much more than rear one.
I always succeeded in leaving few extra clicks for rear rebound when going to Nationals. We are racing mostly on asphalt here in NE (Devens that is), which is definitely on the grippy side, but three extra clicks (from 6 to 3) where always needed on my shocks in the past. That way car felt pretty much the same between two surfaces with different grip levels, which made it much easier to drive.

I have to add that on one occasion, I had to add 100 lb extra spring in the rear when I got there, but that is not an option for stock cars.

kyoo

iTrader: (29)

rear sway bar is for sure the way to go for the 8/9s. not much oversteer on demand